This application relates generally to a device and method for making the device for improved temperature sensing and more specifically to improved high-sensitivity thermal sensing on the micro-scale and nano-scale by improved temperature sensors.
Photo-lithographically patterned spring structures (sometimes referred to as “micro-springs”) represent one type of micro-machined structure that has been developed, for example, to produce low cost temperature probes. Such structures have also been used as probe cards, and to provide electrical connections between integrated circuits, circuit boards, and electrode arrays, and for producing other devices such as inductors, variable capacitors, and actuated mirrors, among other uses. Conventional spring structures include a spring metal finger (beam) having a flat anchor portion secured to a substrate, and a curved free cantilever portion extending from the anchor portion and bending away or coming out from the substrate (i.e., such that an air-gap is defined between the tip of the spring metal finger and the substrate to which the anchor portion is attached).
The spring metal finger is formed from a stress-engineered metal film (i.e., a metal film fabricated such that its lower portions have a different internal stress than its upper portions) that is at least partially formed on a release material layer. The free cantilever portion of the spring metal finger bends away from the substrate when the release material located under the spring finger is etched away. The internal stress gradient is produced in the spring metal by layering different metals having the desired stress characteristics, or using a single metal by altering the fabrication parameters. The stress-engineered metal films used to form spring structures are processed by sputtering deposition methods, and/or plating deposition methods
It is considered that additional advances to the spring structures previously disclosed, when used in connection with temperature probes would be useful in a number of environments. The following therefore discloses advances to temperature probes employing processing methods used in making spring structures.